Earth Sciences 2266F/G Lecture Notes - Lecture 4: Ediacaran Biota, Cambrian Explosion, Filter Feeder
23 Jan 2020
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All 3 clades appear by early cambrian (results of explosion: burst of diversification when organisms produce skeletons, main phyla existed in ediacaran that still live today (chidarians/coelenterates) Ediacaran biota: main type of feeding is suspension feeding (from water column, all animals soft bodied, low diversity and no predation. Huge burst in diversity: organisms had hard parts (mineralized, diversity started when organisms started eating each other. Those getting eaten respond by making hard parts and predators evolved better mouth parts. Cause its so important organisms make skeleton out of it for times of deprivation (backup) Evolution of vertebrates: all craniates characterized by cranium. Fossil stem vertebrates : stem vert appeared during/after cambrian, ancestral to cyclostomes, similar primitive characteristic to hagfish/lampreys. Conodonts tooth-like made out of phosphate: well-perserved but only soft parts came to light. Amoured jawless fishes ostracoderms : not all of them are directly related to each other. Agnatha (jawless fish)-use to refer to all jawless fish.
